SHAPE Society

1. Towards Immune Modulation
against Vulnerable Plaque
Göran K Hansson
Center for Molecular Medicine
Karolinska Institutet
Stockholm, Sweden
Vulnerable Plaque Symposium
Chicago, IL, November 2002

2. Hansson, Libby, Schönbeck & Yan, Circ Res 2002

3. Potential targets for
immunomodulation of
atherosclerosis
• Specific antigens
– oxLDL, HSP65, β2GpI,
microbial
• C pneum, CMV, others
• Co-stimulatory
molecules
– CD40/CD40L, CD28/B7
• Cytokines
– IFNγ, TNFα (aggravating)
– IL-10, TGFβ (protective)
• Vaccines
• Recombinant proteins
• Antibodies
• Cells
• Small molecule drugs

4. Atherosclerosis in the absence of
adaptive immunity?
(G K Hansson & J Nilsson, in: Crawford & DiMarco, Cardiology)

5. CD4+
T cells aggravate atherosclerosis
in immunodeficient apoExSCID mice
*
ApoE-
SCID
ApoE-
T and B cells No CD4+
T Yes
transfer
Aortic lesion
size
Zhou, Nicoletti,
Elhage & Hansson
Circ 102:2919
2000
ApoE-
SCID

6. Immunosuppression to reduce
CD4+ T cell activity?
• General immunosuppression is likely to
reduce atherosclerosis
– Some support from animal studies
• But substantial side effects
– Infections
– Direct vascular effects of drugs
• Therefore, general immunosuppression is
unlikely to be used to treat atherosclerosis or
even vulnerable plaque

7. Complexity of immune
regulatory networks
• Counterbalancing cell subsets
• Idiotypic antibody networks
• Regulatory cytokines

8. The Th1/Th2 Paradigm
Th
IL-12
MHC
Peptide
TCRTCR
IFN-γ
IL-18
Th1
IFN-γ
MΦ
IFN-γ
B
Ab
DTH
InflammationAPC
APC Th
IL-4
Th2Th2
B
IL-3, 5
IL-4
IL-10
IL-13
-
IL-4, 10, 13
Antibodies
Allergy

9. Hypothesis: Th1/Th2 balance
controls atherosclerosis
– Th1 cells dominate in lesions and are
proatherogenic
• CD4+ Th1 cells (Hansson 89; Uyemura 96; Frostegård 99)
• Interferon-γ, TNF-α; IL-12, IL-18 (Zhou 00; Mallat 01;
Daugherty 01)
–Th2 cytokines that inhibit Th1 may be
antiatherogenic?
– IL-10-/-
B6 mice develop larger fatty streaks
– IL-10 administration reduces disease
» Mallat et al; Pinderski et al. 99

10. Increased atherosclerosis in
IL-10 deficient apoE-/-
mice
IL10-/-
E-/-
IL10+/+
E-/-
Caligiuri, Hansson, Rudling, Michel, Nicoletti 2002
*
100
50
Lesion size
(x 103 µm2)
in 16 wks
old mice

11. Antiatherosclerotic cytokines
- useful for therapy?
• Powerful, direct approach
• Recombinant cytokines available
• But these cytokines are usually
immunosuppressive / antiinflammatory,
therefore
– Increased sensitivity to infections
– Cytokine-specific side effects
• E.g. TGFβ – fibrosis
• Therefore, these cytokines might be useful in
acute coronary syndromes,
• although not in chronic atherosclerosis

12. Inflammation
Repair
Innate immunity / TLRs
Adaptive Th1 immunity
IFN-γ TNF-α, IL-1
Inhibitory cytokines
Cells?
IL-10
TGF-β
Ab?
Accelerated athero
Plaque activation
Reduced athero
Stable plaque
Silent disease
Immune regulation of plaque activity

13. B cells of atherosclerotic mice
carry atheroprotective immunity
0
50
100
150
200
250
Sham Sx Sx Sx
Transfer - - T B
*
*
‡
‡
Lesionsize
Caligiuri et al, JCI 109:745, 2002
ApoE mice
Sx, trf 6 wk age
Analysis 18 wk

14. Atheroprotective immunity
• Carried by spleen B cells
• Reduces lesion size and stage
• Reduces CD4+ T cell infiltration in
lesions
• Correlates with anti-oxLDL antibodies
• Protective effect of antibodies?
– Clearance of oxLDL?

15. Protective immunity against
atherosclerosis
• Can we induce it by immunization?
• A vaccination strategy
against atherosclerosis?

16. Protective immunization
1. Oxidized LDL
Parenteral immunization (sc)
Model: Mutant rabbits, mice
Antigen: OxLDL, MDA-LDL
Freund´s adjuvant
Repeated inj 3 wk intervals
Significant protection after 3 months!
Palinski PNAS 95; Ameli ATVB 96;
George Athero 99; Zhou ATVB 00

17. MDA-LDL ”vaccination”
reduces atherosclerosis
Immunogen (PBS) Plaque MDA-LDL
extract
ApoE-/-
mice
Immun wk 6 / FCA
Boost wk 8,10,12,14
Analysis wk 18
Zhou et al, ATVB 2000

18. Protective immunization
2. Heat shock protein 65/60
• HSP60 released upon cell injury and in
atherosclerosis
– Wick, Xu et al. 1992
• HSP65/60 X-reacts man-microbe
• Mucosal administration of HSP65
– Nasal, oral
• Reduced lesions in LDLR mice
– Maron, Libby, Weiner, Circ 2002
– Harats, Shoenfeld, George, JACC 2002

19. Inflammation
Repair
Innate immunity / TLRs
Adaptive Th1 immunity
IFN-γ TNF-α, IL-1
Inhibitory cytokines
Protective B cells
IL-10
TGF-β
Ab?
MΦ activation
Endothelial activation
Radicals
Proteinases
Prothrombotic state
Antiinflammation
Fibrosis
SMC proliferation
Antibody clearance
Immune regulation of plaque activity
Vaccine

20. Small molecule drugs that
modulate athero-immunity
• Pentoxifyllin
– Inhibits Th1 immune responses
– Inhibits atherosclerosis in mice
• Laurat et al Circ 2001
• Statins
– Inhibit Th1 responses!
• Kwak Nat Med 2000; Youssef Nature 2002
– Inhibit atherosclerosis in mice and men

21. Statins inhibit Th1 immunity
• Downregulate interferon-γ induced
HLA-II transcription in macrophages
– Kwak, Mach et al, Nature Med 2000
• Inhibit Th1 signalling
• Increase Th2 cytokines
• Inhibit autoimmune encephalomyelitis
– Youssef, Steinman et al, Nature 2002

22. Inflammation
Repair
Innate immunity / TLRs
Adaptive Th1 immunity
IFN-γ TNF-α, IL-1
Inhibitory cytokines
Protective B cells
IL-10
TGF-β
Ab
MΦ activation
Endothelial activation
Radicals
Proteinases
Prothrombotic state
Antiinflammation
Fibrosis
SMC proliferation
Antibody clearance
Immune modulation of vulnerable plaque
Vaccines
Drugs